set fire to the heart of man
by HoweverImprobable
Summary: There was silence for a moment on the other end of the radio. Sherlock worried that he had put another person off with his deductions. He didn't want to do that with someone as interesting as a retired army captain turned firefighter. A giggle broke through the radio static. "That," the Captain said, "was amazing." Or, how Sherlock falls a bit in love with firefighter!John.
1. Chapter 1

"Excuse me, sir, but where do you think you're going?"

Sherlock huffed out a sigh and turned around to see who was talking to him. Three firefighters stood before him. The one that had spoken was clearly the leader. He had an additional stripe on his gaudy yellow helmet, and there were two white markings on his collar. They all had matching glares on their faces, as if they were somehow going to be able to intimidate him into moving away from the scene. How quaint. "I'm going to investigate the arson and suspected murder that just occurred here," Sherlock told them, raising an eyebrow as if daring them to argue with him.

The higher-ranking officer scoffed. "You're not doing anything like that," he countered. "The scene hasn't been cleared yet. We've got no confirmation that a murder occurred. This is a Fire Brigade matter. We haven't even let the coppers in on it yet."

"Let me in there and I can confirm whether or not the body found in there was victim to the same murderer that struck three days ago on the other side of town," Sherlock argued. "I'm a consulting detective. I work on my own. You wouldn't be liable if anything happened to me in there. Just let me do my work."

One of the lower-ranked men stepped forward. "Yeah, we're going to have to pass on that. Doesn't matter what sort of private detective you are. You're still going to need to wait outside the tape, and when the proper police arrive, maybe they'll let you tag along with them."

Sherlock should have anticipated that there would be some resistance at this crime scene. For the first arson in this investigation, Lestrade hadn't even gotten the call about a potential murder victim until the body was already in the morgue. Their visits to the scene had taken place long after the fact. This time, though, Lestrade had been notified right away once the body had been located in the flames, and he had called Sherlock in only to find that the firefighters weren't yet done.

Before he could retort, there was a telltale crackle of incoming communication from the radio of man with the white marks on his collar. "Murray, why the hell are you not inside the building yet? You, Wilson, and Patel were meant to already be inside conducting structural assessments," the voice on the radio said.

Murray glared at Sherlock before lifting his radio to reply. "Sorry, Captain, but we've got an issue out here. Some private detective is trying to bully his way onto the scene."

Sherlock rolled his eyes at the vehemence directed his way. Before the other men could process it, he reached out and grabbed the radio for himself. "I'm not a private detective; I'm a consulting detective," he explained. "I'm very good at what I do, and I need to get onto the crime scene right now."

"No offence, mate, but like my boys said, we can't just let a private detective—or consulting detective—waltz onto a scene before we've officially cleared it."

Sherlock narrowed his eyes at the radio as if trying to glare at the man through the device. "Fine. Perhaps a demonstration is in order. Your 'boys' here called you 'Captain,' but that's not an official ranking in the London Fire Brigade. Everything about their posture indicates military career. They're standing at parade rest right now." He cast a pointed glance to the men before him, and they shuffled uncomfortably out of their rigid stances. "You served with them, then, and you were their captain. You're clearly still ranked above these men out here even in your current career, or they wouldn't persist in using your army ranking to refer to you. How's that? Impressed, Captain?"

There was nothing but silence for a moment on the other end of the radio, and Sherlock began to worry that he had perhaps put yet another person off with his deductions. That hadn't been his aim, especially not with someone as interesting as a retired army captain turned firefighter.

A high-pitched giggle broke through the radio static. Sherlock stared, in shock, as the noise filled the air. The men around him seemed to be equally as stunned, though whether that was from the deduction or the reaction was unclear.

"That," the Captain said, "was amazing. You're absolutely right on all counts. I was a captain in the army, and now I'm a watch manager. I technically out-rank the guys you're talking to. Incredible."

Sherlock blinked down at the radio for a moment before tentatively saying, "I could have done better in person, you know."

There was another laugh. "You know, I'm sure you could have. You're brilliant. Murray, let this guy onto the scene. If he's as clever as he sounds, he'll know to avoid the structurally unstable bits."

Murray snatched his radio back from Sherlock with a glare. "With all due respect, Captain—"

"That's enough, Murray. I'm still your supervisor, and you'll let this man into the flat. Make sure he doesn't get himself killed." And Sherlock could practically hear the smile in those words.

—

When Sherlock showed up at a similar scene three days later, it was Lestrade who greeted him rather than a group of firemen. He pushed away any lingering disappointment.

"We've got another one," the DI said as he escorted Sherlock up toward the burnt flat. "Looks to be another female, about thirty years old, bound and gagged like the other two. Definitely the same guy. He's keeping a pattern, too. Every three days, a new victim."

Sherlock took in this information and glanced around as they approached the decimated front of the building. "Last time, they wouldn't let me within twenty yards of the scene. What's changed?"

Lestrade gave Sherlock a wry smirk. "When I got here, the watch manager came over and told me that you and I have permission to enter the scene before the final checks are done. He seemed very impressed by you."

Sherlock turned around and ducked down next to the body, effectively hiding his expression from Lestrade. He knew his cheeks were pink, and there was an irritating smile on his face that he couldn't seem to get rid of. He told himself that it was simply because he was appreciative of the watch manager's cooperation. Nothing more. He had no further interest in the man that the other firefighters called Captain. He still hadn't met the Captain, and that bothered him more than it should have. It didn't matter, though. He hardly cared whether or not he met some almost stranger who had been mildly impressed with his deductions. And if he started to seek out more arson-related cases after this, then it would merely be because of his desire to keep London safe. It would have had nothing to do with any former soldier who happened to think he was brilliant.

—

Sherlock didn't figure it out for another three days. There had been seemingly no connections between the victims or the locations in which they had been held and set ablaze. It took hours of digging through property records and class lists before Sherlock discovered the common factor. Anthony Blaine. He'd gone to primary school with the first victim and secondary school with the second and third. His family had also been previous owners of the three flats that had been targeted thus far. There was only one flat left before their current residence, and Sherlock wasted no time in getting there. If the pattern held as expected, then Blaine would attempt to kill again before the day was out.

When he arrived at the scene, there was already smoke billowing out of the second floor windows. It was pouring rain, and he deigned to think that perhaps the water would make the fire slower to progress. His coat and scarf were utterly soaked within seconds of arriving. No firefighters were on the scene yet, though Sherlock suspected that his cabbie was going to call it in. He didn't wait around to confirm that, though. If the fire had just started, then it was entirely possible that the victim was still alive in there.

He spared a brief moment to text Lestrade before he was dashing forward into the building, starting to cough almost immediately as he pushed through the thick cloud of smoke. He could feel it burning down his lungs, and he knew that he wouldn't be able to last in that place for very long. The fire was still relatively small, but it was spreading fast. He could detect a faintly sweet smell in the air, and he knew enough to understand that there must have been an accelerant present. His eyes burned, but he forced himself to continue looking around. He wasn't going to let this girl die on his account. No, he would get her out of this alive.

In the end, he nearly tripped over her. With his eyes as watery as they were, it was slightly more difficult to see than he'd anticipated. She appeared to be barely conscious, bound and gagged just like the previous victims. He dropped to his knees beside her without a second thought, pulling the gag from her mouth and untying the restraints around her wrists.

"Are you all right?" he asked, having to practically shout over the crackling of the fire overtaking flat's appliances.

She nodded but didn't speak as she suddenly started coughing.

Sherlock hurriedly untied his scarf from around his neck. The fabric was damp enough that it might actually help prevent further smoke inhalation. "Here," he said, balling it up and pressing it over her nose and mouth lightly. "Hold this right there. It should help."

He supported her weight as she lifted herself off the ground. He wasn't sure what had been done to her, but she was weak at the very least, her legs seeming to barely support her. He led the way toward the entrance through which he had come in, but there was now a large patch of flames that seemed to aggressively guard the door. Sherlock cursed, and he started coughing again. He found it difficult to stop. He felt dizzy, but he needed to get them out safely. He wouldn't let Blaine claim another victim.

Just as he felt on the verge of collapsing, two firefighters stepped calmly through the flames, protected by their thick boots and trousers. One of them—a lower-ranking member, he couldn't help but notice—stepped forward and took the victim off of his shoulder. Sherlock stumbled to the side with the loss of her weight, and he started to wonder whether or not they had been supporting one another equally all along. The other firefighter—white helmet, signaling higher rank—scooped Sherlock in his arms without a moment of hesitation.

"I'm—" Sherlock paused to cough a bit more. "I'm fairly certain this isn't how firefighters are meant to rescue civilians." He was being carried bridal style rather than in the traditional firemen's hold. It must have been highly against protocol.

"I didn't think you'd appreciate being slung over my shoulder," the firefighter told him with an obvious smile. Sherlock recognised that voice, but when he tried to say as much, he only ended up coughing more. "Don't try talking just yet. I'm John Watson, watch manager for this group of men. We talked on the radio about a week ago. You called me Captain." Sherlock nodded to show that he remembered the man as they started moving toward the exit. "I've been tracking your progress on this case, you know. You're brilliant. Really, quite impressive. I knew you'd be amazing after we talked, but I didn't expect you to actually put everything together like this."

Sherlock could feel his face heating, and he wasn't sure what had caused it. He blamed it on the heat, even though they were now crossing the threshold back onto the pavement in the cool, rainy air.

"I'd be more impressed, though," John continued with a practically audible smirk, "if you didn't end up having to be treated by a medic for smoke inhalation."

Sherlock tried to tell John to shut up, but it came out as a pathetic wheeze instead. He settled for glaring at the man as he was set down gently on a stretcher beside an ambulance. John went about getting him an oxygen tank and setting the mask over his nose and mouth. Only then did he lift up the visor on his helmet. Without that reflective, tinted bit of plastic in his way, Sherlock could finally see John's face, could finally take in all of him. He sat up, a bit shocked by what he saw.

John Watson was attractive. Fairly unassuming face, evidence of the capacity for very stern or seductive expressions. Sandy blond-grey hair. Relatively short stature but with a strength in his body from his army training. Dark eyes that looked like they might have been blue. In addition, his familiarity with the ambulance indicated a medical background. He was therefore an attractive former doctor-soldier who had become a firefighter, likely for the added adrenaline rush. He was perfect.

Sherlock was glad that he had the oxygen mask over his nose and mouth to remind him to breathe, because he was fairly certain he'd have forgotten otherwise. Of course, that merely made him look more foolish in comparison to possibly the most attractive man he'd ever seen.

John furrowed his brow at Sherlock's expression. "Are you feeling all right? You look a little flushed." He pressed the back of one hand against Sherlock's forehead and seemed satisfied that he didn't have a fever. He seemed to realise, then, that there might be another cause for the pinkness in Sherlock's cheeks. He smirked and began needlessly wiping soot out of Sherlock's hair, which did nothing to help him keep his face a normal colour. "When I heard that voice of yours for the first time," John said, "I knew your body had to be amazing as well, but I have to say, you've exceeded my expectations."

Sherlock started to wonder whether or not it was possible to actually spontaneously combust. He supposed he was lucky that there was a firefighter standing so close to him. A little too close. Sherlock was starting to get ridiculous ideas about reaching out and touching John, and that was just not on. He was meant to be married to his work, after all. Besides that, John was just joking, surely. He couldn't have actually meant it.

John pulled away right then, and Sherlock panicked for a moment, thinking he had said all of that aloud, but John was smiling and didn't seem put off. "I have to go brief that detective inspector about all of this," John explained. "Don't go anywhere, and keep that mask on until you feel like you can talk without coughing or wheezing." He winked before walking away, and Sherlock collapsed back onto the stretcher and flung an arm over his eyes despairingly. He was so, totally helpless, and John was so, totally hot.

* * *

 _Let me know what you thought! The next and final chapter will be up by next Wednesday!_


	2. Chapter 2

Sherlock was in the process of discharging himself from the care of the paramedics when John walked over and found him again. John's helmet and extraneous gear had been dropped off somewhere, it seemed, and he was merely wearing his bulky uniform. God, he was attractive. While he was secretly thrilled that John had sought him out, he was also slightly devastated, knowing that he wouldn't be able to think properly until at least twenty-four hours after John left his presence for good.

"I definitely like you better without the oxygen mask on," John said with a pleasant smile as he reached the ambulance. Sherlock wasn't sure how to respond to that, and any hopes of coming up with the right words were eliminated as John reached out to stroke his fingers against Sherlock's cheek. "I think I'd like you even better without all this ash." John lifted his hand to show that his fingertips had come away from Sherlock's skin covered in a thin layer of grey dust.

Sherlock had meant to come up with an excuse to leave without encouraging further contact between them. John didn't mean to be so friendly. The touch was just to prove he was covered in ash, and the apparent interest was fascination with his mind and professional curiosity about his condition. Trying to keep up contact between them would therefore only set him up for rejection. Instead of the planned excuse, though, when he opened his mouth, he found himself asking, "Dinner?"

His first thought was to backtrack, to say that he hadn't been offering and had merely been explaining his plans for the rest of the evening, but John smiled over at him as if he'd said something particularly clever, and he found that he didn't regret anything that made John look at him like that.

"Starving," John said, and then Sherlock was smiling, too.

* * *

They went to a Chinese restaurant that stayed open late, and it was surprisingly easy to keep the conversation going while they ate. John talked about his time in the army, and Sherlock pretended he was listening, though it was hard to actually do so when his mind insisted on conjuring the image of John in a military uniform. Sherlock talked about his experiments and past cases, and John seemed genuinely intrigued. When they'd finished their meals, even though the owners owed Sherlock a favour, John still insisted on paying, and Sherlock acted as though his heart wasn't beating out of his chest at the gesture.

Throughout all of that, Sherlock had been able to maintain the outward appearance of calmness. It was only when their shared cab pulled up outside his flat that he began to lose his grip on that nonchalant mask.

"Do you want to come in?" he blurted out and immediately regretted it. "I mean, your current salary is adequate at best, and your army pension likely contributes very little. Your flat right now must be quite terrible, then. I've got an extra bedroom, and I've been looking for a flatmate." That much was a lie. Mrs. Hudson had thought that it would be good of him to find someone to live with, but Sherlock had never actively looked.

John quirked an eyebrow up and thankfully looked amused rather than horrified. "Spot on, as always," he said with a small smile. "I'll have to give more consideration to moving in, obviously, but I'd love to come up."

Sherlock let out a relieved breath and slipped out of the cab, hurrying to unlock the door to the building before John changed his mind.

"This is…an interesting place," John commented once they were upstairs in the sitting room of 221B.

Sherlock shifted nervously and fluttered around the room, trying to sort loose papers into neater piles. "Well, with the case going on, it's been hard to keep things in order." Another lie, of course. There was never much of an order in the sitting room. "Do you want something to drink?" he asked, remembering those manners he had always been lectured about. He dashed into the kitchen and pulled open the door of the fridge. That revealed a sad selection indeed. "I've got…wine? Or water, I suppose." He was sure John would refuse the wine, as that implied that they would spend more time together that night drinking it.

John surprised him, though, when he said, "I'd love a glass of wine." John smiled over at him from where he'd made himself comfortable on the sofa.

Sherlock's heart skipped as he considered how good John looked in his flat. John was still wearing his uniform. The black and yellow material should have looked tacky at best, but instead, it seemed to be a particularly good look on John. Sherlock couldn't help but notice that it would be even better if John took his jacket. He licked his lips as he pictured John in his vest and trousers, still somewhat dirtied from trudging through a fire earlier.

He forced himself to get it together. To distract himself from the image, he pulled out his bottle of Cabernet and two glasses, giving them each a healthy portion. He passed John his wine and sat down beside him on the sofa, careful to keep himself at a respectable distance. He drank half his glass in one go as John watched him with amusement.

"You don't pace yourself much, do you?" John asked him with a smirk.

Sherlock offered a small smile in return. "Patience is not something I'm known for."

John shifted closer and lifted his free arm up to rest on the back of the sofa. Sherlock felt his stomach flip. It was almost like John was making a move on him, but he knew it was foolish to truly believe that without further proof.

"I'm not one for pacing myself, either," John murmured, and his fingers came up to brush gently at the hair behind Sherlock's ear. Further proof indeed.

Sherlock opened his mouth, shut it again, and then swallowed down the last of his wine. Except that, with his wine gone, he had nothing to occupy himself with as a distraction from John. He could feel his cheeks turning pinker by the second, and he made sure to keep eye contact with John. If he looked confident enough, his blush might appear to be a trick of the lighting. How could he be confident, though, when he was entirely out of his depth?

"Do you want this?" John asked him, his hand now drifting down to cup Sherlock's cheek.

Sherlock considered saying no. He'd always turned down advances in the past, and this _had_ to be an advance. There was no other logical explanation for John's behaviour. Emotional entanglements would only slow him down. The work was what mattered, and having his mind muddled by sentiment would be detrimental. He imagined that John would be disappointed with the rejection, but he would surely move on quickly enough. An attractive and simply fascinating former soldier, doctor, and fireman all in one, there was no way John would stay single for long. They would still see one another on occasion during arson cases, of course, and Sherlock would be able to experience John being interesting and attractive and capable, though he would also be forced to see evidence of whatever knew partner John was bound to find for himself. He decided that he didn't like the thought of that last part at all.

"Yes," he found himself saying, in spite of the rational reasons for turning John down. He cleared his throat and set his wine glass down on the coffee table. "That is to say, yes, I want this." He wasn't one for casual sex—or sex at all, really—but John had paid for dinner, and there was something about their interactions that indicated more than just carnal interest.

John huffed out a surprised laugh and smiled broadly over at him, and Sherlock decided that he had absolutely made the right call. "Good," John murmured, and before Sherlock could even think of a response, their lips were pressed together.

He had kissed people before. There had been Susan when he was five, though that had merely been the two of them tripping and smacking against one another. The touching of lips had been accidental and painful. Then there was Victor in sixth form. That had been wet and sloppy and not entirely comfortable. The only people since then had been persons of interest in cases he was working. So he had done this before, yes, but his experience was still far too limited to have prepared him for kissing John Watson.

It started out slow and chaste, as if John knew that he would need time to adjust to the feeling. As soon as he got a bit more comfortable with the kiss, John's tongue slipped out against his lips and worked its way into his mouth. The kiss still remained relatively slow and sweet until Sherlock heard one of them (him, most likely) making soft, needy sounds into it. After that, John didn't seem to hold back any longer. He surged forward until Sherlock was sprawled out on his back on the sofa, John braced above him. Capable hands worked their way into Sherlock's hair, alternating between tugging and petting in a way that made Sherlock glad he was already lying down. There was a heat building inside of him that seemed to correspond with the movement of John's tongue against his. He was saved from having to figure out what to do with his hands when John reached down and pinned both his wrists above his head with one hand. God, John was good at this. Sherlock let out a high, desperate noise, and he rocked his hips up on instinct, startling another moan out of him when he pressed himself against John.

John broke the kiss and bent down to pant against his neck. "You're so hot. How did you get to be so hot?" He nibbled at Sherlock's skin, and at the whine that move earned him, he smirked and started to suck on Sherlock's neck in earnest. He only pulled back when there was clearly going to be a visible mark lingering in that spot for days.

John leaned back, and when he did so, he ended up sitting with his hips pressed right up against Sherlock's. It was obvious at that point that they were both incredibly aroused, and knowing that he wasn't the only one in this state sent another spike of need through Sherlock. John groaned at the contact, too, and Sherlock was certain he had never heard a more erotic sound in his life.

"Let me know if this is moving too fast," John said, managing to work through his lust with obvious effort to be reasonable right then.

Sherlock tried to put on his usual air of haughty indifference, but it was difficult to manage when his cheeks were red and he was breathless. "All your clothes are still on, so I'd say this isn't moving _fast enough_."

John laughed, a high, pleased giggle, and Sherlock positively melted underneath him. John leaned down to press a kiss to Sherlock's nose. "Well, we'll just have to move things along, then." He stripped his jacket off, leaving only his vest covering his chest.

John was even sexier like that than Sherlock had previously imagined. Sherlock licked his lips and reached out one hand to rest on John's chest, moving it slowly down the man's front and simply feeling the muscle and slight traces of subcutaneous fat. Sherlock noted the scar that peeked out from behind one side of John's vest. He knew that too much attention to it might make John uncomfortable, so he merely passed his fingers over it gently before moving on.

John allowed this slow exploration to occur with a hint of amusement on his face. "Bedroom?" he asked. "If you want this to move in that direction."

Yes. Bedroom. They would be able to do so much more in the bedroom. He at least had lubricant in there. He shivered at the thought of all they could do with that. This certainly wasn't moving fast enough. He shoved at John, urging him to get up. John did so with noticeable confusion but didn't seem concerned that the events of the night were stopping. Good. Sherlock didn't want John to worry about that. He pushed himself up from the sofa and said, "This way," before walking down the hall toward his room. He felt unsure of himself right then. It was easy when they were pressed together, but walking together was strange. Should he have been holding John's hand? Should he have been giving John more space? He really didn't know.

Not wanting to waste any more time in that uncertain transit, as soon as he walked into his room, he perched himself on the middle of the bed. Instead of joining him immediately, John simply stared at him for a moment before walking up to the bed.

"You are _gorgeous_ ," John told him, nothing but sincerity in his voice.

Sherlock felt his cheeks heat. "You think so?"

John nodded, crawling onto the bed now. "Yes, I do. Absolutely gorgeous. Breathtaking. Out of this world." He moved until he'd resumed his earlier position on top of Sherlock. He pressed a few soft kisses to Sherlock's neck, his cheeks, his lips, before passion began to seep in.

Sherlock wrapped his arms around John's neck and pulled him down to deepen the kiss. He was feeling more confident in this whole kissing business by that point, learning from John, mimicking his movements and experimenting with new forms. He hoped that they would continue this arrangement for some time afterward so that he could get as good at kissing as John obviously was.

"We might want to start getting rid of these clothes," John noted, pulling back just enough to strip his vest off.

Sherlock had been so wrapped up in the kiss that he'd hardly remembered how eager he was for them to both be naked. He was glad that John seemed to be ready to remind him how to keep things moving every so often. He propped himself up on his elbows and hurriedly undid the buttons of his ash-dirtied shirt. He tossed it on the floor once he'd gotten it off and moved his hands down to his belt, fumbling with it uselessly until he finally managed to get it undone. John was still sitting on his hips, so neither of them were really in any position to take their trousers off right then, but Sherlock found that he couldn't be bothered with that, especially not when John bent down and began to lick and bite at Sherlock's nipples.

He felt as if an electric shock had gone through him. It was maddening and arousing and he couldn't get enough. " _Oh_ ," he gasped as he arched his body up.

John pulled back and laughed lightly, though the noise was so tinged with arousal that Sherlock couldn't even be upset that he was being laughed at. "I had no idea you'd be so responsive," John commented, and he seemed surprisingly enraptured by that fact. He teased Sherlock's other nipple while his hands dragged down the pale body before him until he was cupping the front of Sherlock's trousers.

Sherlock tossed his head back and moaned, hips bucking up into John's hand. "We need—to get all of these clothes off— _now_ ," he said, his words choppy and disjointed as they were interrupted by little gasps.

John rolled off of him, and Sherlock couldn't help but whine. John laughed again and kissed his shoulder in an attempt at reassurance. "I'm just moving to get my clothes off like you asked," he said. "When we're both undressed, I promise I'll be right back on top of you."

Sherlock supposed he could deal with that. He quickly divested himself of his own trousers and pants, only slightly self-conscious about John seeing him totally naked. He was perfectly average in size, so he was sure he had no need to be embarrassed, but, of course, he had never been this exposed in front of someone else in recent years.

He forgot all about his own body as soon as John's was revealed. "Oh," he breathed, eyes going wide as he took in the sight before him. John was…big. Bigger than average, certainly, and thicker, too. Sherlock's mouth watered. He needed that inside of him.

He immediately twisted over the side of the bed toward his bedside table so quickly that he almost tumbled to the floor. John luckily grabbed his waist before he could really fall.

"Whoa," John said, not moving his hands away as if he feared Sherlock would throw himself to the ground if he let go. "What are you doing?" He loosened his grip suddenly but didn't let go entirely. "Do you want to stop? Is that what this is?"

Sherlock rolled his eyes, feeling more confident. He had a definite mission in mind, and he would not let his own uncertainty deter him from it. "I'm not stopping this," he said, wiggling his arse a bit just to feel John's hands tighten around him. "I'm getting—" He fumbled around in his drawer for a few moments before pulling out a small bottle, triumphant. "I was getting this." He tossed the lube over at John and pulled himself back up on the bed properly. "We'll be needing it."

John seemed torn between amusement and arousal as he took in what Sherlock had been grabbing. "You're just perfect, aren't you?" he murmured before leaning down to kiss Sherlock again. This time, the kiss was a bit sloppy and incredibly hot.

Sherlock wrapped one leg around John's waist and tried to pull him down, but John refused to move. Sherlock whined and tried to rock his hips up against John's, but there was too much distance between them for him to get any friction.

He would have complained verbally had he not felt three slick digits pressed up against his perineum. A shot of electric arousal went through him at the touch. When had John opened the bottle of lube? How had Sherlock not noticed this? His whole body stilled as he adjusted to the new feeling.

"Is this all right?" John asked, and Sherlock would have rolled his eyes again had he not been so preoccupied with the fact that John's fingers were so close to where he needed them.

Sherlock nodded distractedly in reply and tried to angle his hips to make John's hand slip a little farther back.

John smirked. "Eager, are we? Don't worry, sweetheart. I'm going to take _very_ good care of you."

Sherlock shuddered. There was something about the way John talked to him that made him feel hot all over.

John's fingers shifted until they were pressed right up against his hole. One finger massaged around the muscle there until just the tip of it was able to slip in. Sherlock felt like he couldn't breathe. He pressed back, desperate for more of it. He'd done this on his own before, of course, but John's fingers were so much wider than his own. Besides, there was an intoxicating loss of control now that it was someone else performing this act rather than just himself.

"More," Sherlock said, and John pressed his index finger fully inside. "More," Sherlock repeated, and John started to stretch him enough to take two fingers. It went on like that, with Sherlock panting, "More," and John never denying him, until finally three fingers were pumping in and out of him.

Sherlock's head was thrown back, his cheeks flushed red, forehead covered in sweat. He imagined he must look a mess, and he was surprised that John apparently hadn't lost interest. On the contrary, given the little sympathetic groans John was making, it seemed that this whole experience was mutually pleasurable.

Sherlock licked his palm and reached down to wrap his hand around John's cock. The movement of John's fingers in his arse stuttered to a halt as Sherlock tentatively began to stroke. He had never done this with someone else before, and the angle was odd. He decided that if he couldn't pleasure John with his hand just yet, he could certainly do it another way.

"I want you inside of me," he said, and while he'd tried to make it sound sexy, he only ended up coming off needy. He was too turned on to care.

John groaned again and rocked his hips up into Sherlock's hand. "Are you sure?" he asked, and Sherlock would have told him off for his over-consideration had he not been so distracted by the prospect of getting John to fuck him.

"Yes, yes, I'm sure," he said hurriedly. "Just _do it_."

John pulled his fingers out entirely and was kind enough not to mention the near-sob that ripped its way out of Sherlock at the sudden emptiness. "Shh, baby, it's all right," John assured him softly. He poured out some of the lube to slick up his cock. Moving in between Sherlock's legs, he lined himself up and said, "I'm going to push into you now. Stop me if it hurts." He nudged forward until just the head pressed in.

Sherlock bit his lip to stifle his moan, but even that didn't do much to decrease his volume.

"Like that, do you?" John panted as he inched in further.

By the time his entire cock was buried in Sherlock's arse, both of them were out of breath, and Sherlock was letting out soft, desperate noises with every exhale.

" _Please_ ," Sherlock said, and John practically growled in response.

After that, there was no trace of any of the softness of their earlier kisses. No, from that point on, it was pure, carnal passion. John gripped his wrists in one hand like he'd done on the sofa and propped one of Sherlock's legs on his good shoulder. He used his other hand to brace himself above the other man as he pounded into him. John set a fast, brutal rhythm that left Sherlock positively howling at every brush against his prostate. John's every breath was punctuated with, " _Fuck_ yes," or, "That's it, baby, take it," or, "God, you're gorgeous," and Sherlock's ability to speak steadily degraded until all he was able to do was moan out something that sounded vaguely like John's name.

After one particularly rough thrust, Sherlock felt his whole body begin to heat up as white-hot arousal steadily bloomed in his abdomen. "I'm— _I'm_ —" And then he was coming without a hand on him. His eyes wide, pure pleasure flooding through his veins, he cried out as he made a mess of himself.

John fucked him through it, and even after he'd started to whimper from delicious over-stimulation, John pounded into him until his rhythm finally stuttered and he stilled. Sherlock groaned at the feeling of John coming inside of him and was distantly grateful that John hadn't insisted on using a condom.

John rested his forehead against Sherlock's shoulder, and as the adrenaline began to fade, Sherlock started to worry that John was hiding some sort of disappointed expression. Those concerns dissolved, however, when a high giggle bubbled out of the man on top.

"Are you _laughing_?" Sherlock asked, and he'd meant to sound indignant but only sounded amused in turn.

"Rush of endorphins," John said cheerily by way of explanation. He lifted his head, grinning, and kissed Sherlock gently. The fact that he still wanted them to kiss was certainly reassuring.

John pulled out, and Sherlock grimaced at the feeling of wetness seeping out of him as well. "I think I'd like that much more if I was still hard," he murmured.

John smiled at him before bending between his legs to check his hole for damage. He pressed a kiss to Sherlock's upper thigh before slipping off the bed entirely. "I'll help you get cleaned up, promise."

John presumably found the loo and managed to fetch them a wet flannel, which he—as promised—used to wipe up the mess Sherlock's arse had become and the ejaculate drying on his chest. John then carelessly tossed the flannel onto the floor, and Sherlock found that he loved him a bit. Not genuinely, of course, but there was something about John's casual way of fitting into the flat, into Sherlock's life, that made it seem as though they'd been living with one another for years. It was intoxicating, and he didn't want it to end.

* * *

The following day, Lestrade texted with a case. An interesting one, too. Sherlock simply couldn't pass it up. John had laughed at him over breakfast, saying, "You're cute when you're excited about a case." After that, Sherlock had forgotten about the investigation for half an hour while he kissed John sweetly for the compliment.

By the time he showed up at the crime scene, he was nearly an hour late, as he'd had to shower and change and help John clean up a bit.

Sally clearly didn't appreciate his tardiness. "You're late," she said, glancing up only briefly from her notebook before doing a double-take. "Who's this?" She looked over at John, who was standing in his fireman's uniform at Sherlock's side.

"This is John Watson," Sherlock said, ducking beneath the yellow tape. "He's with me."

John smiled over at Sally and followed Sherlock under the tape. "I'm with him," he reiterated.

Sally was so shocked at the sight of Sherlock with another living being that it took her until they'd gotten inside the building to yell, "You can't just bring _guests_ to crime scenes!"

Lestrade was drawn out into entryway by the shout. "What's going on here?" he demanded. He frowned over at John. "Captain Watson, right? The firefighter?"

"It's actually still technically Dr. Watson, but, yeah, that's me."

"Right," Lestrade said. "What are you doing here, Dr. Watson? This isn't an arson."

"I asked him to be here." Sherlock stepped up to John's side. Not too close, of course, because he wasn't sure John wanted others to know about their intimacy with one another. "He's a doctor who is used to life-and-death situations. He'll be very helpful."

John smiled up at him, as if surprised that Sherlock would consider him an asset. His expression turned to a smirk as he looked back over at Donovan and Lestrade. "I also happen to be dating him, so he might be a little biased," John said, wrapping one arm around Sherlock's waist and pulling him close.

Sherlock flushed and smiled, and John grinned right back at him, while Lestrade and Sally looked on with disbelief. He and John couldn't help but laugh at their expressions as they moved into the other room to get a proper look at the crime scene. Oddly enough, John helped him with the case, both by pointing out obvious and easily over-looked clues and by providing Sherlock with someone he desperately wanted to impress. John kissed him briefly when he'd figured it out, and Lestrade appeared to be too glad for the quick solve to care about the public display of affection or about the fact that John and Sherlock walked away from the scene hand-in-hand.

 _This,_ Sherlock thought, _feels right. It has to last._

And it did.


End file.
